Story highlights

Before her death in police custody, she was pulled over for a routine traffic stop

"Being a black person in America is very, very hard," she said in a video posted in April

(CNN)Sandra Bland, like many people her age, regularly voiced opinions about racism and other topics on social media.

The 28-year-old posted about going natural with her hair, the "Black Lives Matter" movement, and even offered a "shout out" to a girl who handed her a bottle of water after a John Legend concert.

On Facebook, using the #SandySpeaks hashtag, she would monologue about police brutality and the plight of African Americans.

"Being a black person in America is very, very hard," she said in a video posted in April. "At the moment black lives matter. They matter."

Her last tweet, dated June 18, offered prayers for the nine people gunned down by a young white man a day earlier during a Bible study meeting at the historically black Emanuel African Methodist Episcopal Church in Charleston, South Carolina.

But of the snippets of a short life that can be gleaned from social media posts, none was more haunting than an April 8 tweet from Bland saying, "AT FIRST THEY USED A NOOSE, NOW ALL THEY DO IS SHOOT #BlackLivesMatter #SandySpeaks." The tweet links to her Instagram account, where she posted an illustration of a young black man wearing a noose fashioned from the American flag.

Her death is being investigated as a murder, though authorities have said Bland appeared to have hanged herself. The cause of her death has been determined to be hanging; the manner of death, suicide, according to early autopsy results that do not show obvious signs of a violent struggle.

Her family has said the idea that she committed suicide is unthinkable.

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Bland was not clinically diagnosed with depression or on any medication and was "ecstatic" at the prospect of starting a new job at her alma mater in Texas, family attorney Cannon Lambert said.

"Right now Sandy is speaking," he said. "She's speaking and saying, 'Find the truth. Find the answers.'"

Waller County Sheriff R. Glenn Smith said Bland told the county jailer during her intake that she had previously tried to kill herself.

Authorities released jail intake forms late Wednesday that appear to show Bland answering "yes" to the following questions: Have you ever been very depressed? Do you feel this way now? Have you had thoughts of killing yourself in the last year? Have you ever attempted suicide?

But, later, on a different sheet, the word "no" appears next to questions about mental illness and attempted suicide. A reason for the apparent discrepancy was not immediately clear.

Separately, an inmate who was held in a cell adjacent to Bland told CNN she did not hear any commotion or screaming that would suggest foul play before Bland was found dead.

The woman said Bland wasn't eating, and was emotional and often crying during her three days in the jail. She was also stressed about missing her first day of work at her new job, said Alexandria Pyle.

"She found out her bond was $5,000, and no one -- she was calling and calling -- and no one was answering, and then after that she just broke down. She was crying and crying," Pyle said.

Bland was taking a new job at Prairie View A&M University in Texas. She had graduated from the historically black college in 2009 and was returning as a student ambassador, according to family members.

"To know Sandy was to love her," said Sharon Cooper, one of Bland's four sisters.

"She was someone who was extremely spontaneous, spunky, outgoing, truly filled with life and joy. When you think through the circumstances that have been shared with us to this point, it is unimaginable and difficult for us to wrap our minds around the Sandy that we knew -- for this to be characteristic of her."

On Tuesday night, family and friends held a memorial service for Bland on the Texas campus where she was supposed to start her new job, CNN affiliate KPRC reported.

Geneva Reed-Veal, Bland's mother, recalled one of her last conversations with her daughter.

"She said, 'Momma, now I know what my purpose is. My purpose is to go back to Texas. My purpose is to stop all social injustice in the South.' "

At Prairie View A&M University, Bland was a member of the Sigma Gamma Rho. The sorority issued a statement asking that -- at the request of Bland's family -- members "refrain from posting social media messages about this matter" and not participate in protests or marches.

"We will respect the wishes of the family and take no action at this time," the statement said.

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Sandra Bland jail video released04:54

Unlike Bland's outspokenness on issues of race and justice, her family has taken a more wait-and-see approach to the investigation into her death.

"What they are seeking is an opportunity to first say thank you to the community, but also very much wanting to ask for calm," Lambert said. "We don't want to see Sandy politicized. We don't want to see her life politicized, and we don't want to see her death politicized."

A newly released dashcam video of Texas state Trooper Brian Encinia pulling Bland over for allegedly failing to use her turn signal shows how she reacted the day of her arrest. It started as a normal conversation but grew tense after Encinia asked her to put out her cigarette.

"I am in my car. Why do I have to put out my cigarette?" Bland said.

"You can step on out now," Encinia replied.

Bland refused to get out of her car. The trooper opened her door and tried to pull her out of the vehicle.

In the video, Encinia told Bland she was under arrest. She repeatedly asked why. The trooper does not answer, other than to say, "I am giving you a lawful order."

At one point, after Encina aimed what appeared to be a Taser at Bland, she stepped out of her car. Later, she can be heard saying: "You're a real man now. You just slammed me, knocked my head in the ground."

Cooper said she had seen the whole video.

"I'm infuriated and everybody else should be infuriated," she said.

Bland was a graduate of Willowbrook High School in Villa Park, Illinois, where she ran track and played volleyball, The Chicago Tribune reported. She was also a varsity cheerleader and part of the marching band. As a member of the high school's World Languages Honor Society, she was required to have at least an A average, according to the newspaper.

Bland recently worked on the administrative staff of a food service equipment and supplies dealer in Illinois, according to the Tribune. She and her family were members of DuPage African Methodist Episcopal Church, where her funeral will be held.

"We have successfully been able to go and get our sister and daughter and bring her home," Lambert said. "The family is preparing for the homegoing celebration."

Cooper said she will miss luring Bland to her house with offers of playtime with her niece "just because I secretly want to see her," according to KPRC. She said a Maroon 5 concert she attended with Bland in February was "the last concert that I will ever go to with her."

"Based on the Sandy I knew, this is unfathomable to me," Cooper said of her sister's possible suicide. "People who knew her, truly knew her, the depth of her, that's unfathomable right now."

Cooper urged supporters to continue to express their solidarity via social media, in the same way Bland spoke out about other injustices.

"Please keep tweeting, keep Facebooking and Instagraming," she said. "Keep utilizing the hashtag #JusticeforSandy ... Keep hashtagging #SayHerName. The minute you forget her name you forget her character."

In her last public words before her death, Bland expressed gratitude to a man who captured her arrest on cellphone video.

"Thank you for recording. Thank you. For a traffic signal. Slammed me into the ground and everything," she is heard saying.

Her family was grateful, too.

"I would advocate that any time that people see a situation that rises to a level of concern, that they video," Lambert said. "Sandy herself said thank you."